How can you upload an image from within a settings page?

Question

Is there an easy way to include an upload box to your settings page?

I am building an Open Graph options page and I like users to upload a standard image directly from that page.

Answer 1

WordPress provides a convenient function for just this purpose: wp_handle_upload().

Assuming that you already have the appropriate file form field in your settings page, and that you're using register_setting() for your options, and therefore already have an options validation callback, simply handle the file form field data using wp_handle_upload(). Here's an example:

<?php
// Validate file fields
else if ( 'file' == $optiondetails['type'] ) {
    if ( isset( $input[$setting] ) ) {
        // Only update setting if input value is in the list of valid options
        $setting_file = $setting . '_file';
        $valid_input[$setting] = ( isset( $_FILES[$setting_file] ) ? theme-slug_image_upload( $setting, $input ) : $valid_input[$setting] );
    }
}
?>

Then, you just need to define that theme-slug_image_upload() callback, using wp_handle_upload():

<?php
function theme-slug_image_upload( $the_file, $input ) {
    $data = $_FILES[$the_file . '_file'];
    if ( '' != $data['name'] )
        $upload = wp_handle_upload( $_FILES[$the_file . '_file'], array( 'test_form' => false ) );
    else
        $upload['url'] = $input[$the_file];
    return $upload['url'];
}
?>

That's pretty much it.

Answer 2

This was more what I wanted:

http://www.webmaster-source.com/2010/01/08/using-the-wordpress-uploader-in-your-plugin-or-theme/

Now to figure out how you can detect if a certain image has been deleted.